What do you mean “this purpose”? The text linked in OP says

> Congestion signalling methods cannot work around this problem either, so our analysis is also valid for Explicit Congestion Notification methods such as Low Latency Low Loss Scalable Throughput (L4S).

L4S (or at least, the dualq implementation) uses a shallow buffer. You can't get 1000ms of latency if your buffer is only 15ms. Although the title claims there's no way round latency spikes, their paper [1] explores the case where latency spikes are traded off against allowing packet loss, which is what you're going to get if you fill a shallow buffer. For real-time traffic, packet dropping is usually preferable.

[1] https://arxiv.org/pdf/2111.00488

though it supports fair-queuing since 2018